Methods: Floor dust samples (n=24) were analyzed as part of an earlier investigation of an office building located in the northeastern United States that had well characterized water intrusion. Genomic DNA was extracted from 5 mg of floor dust. Fungal ITS regions were amplified and sequenced using Sanger sequencing. Sequences were clustered into organizational taxonomic units (OTUs) and sequence identifications were determined by searching the National Center for Biotechnology Information nucleotide database.
Results: A total of 1028 ITS sequences were identified and placed in 288 OTUs. The dust samples were composed of sequences derived from the fungal phyla, Ascomycota (58%), Basidiomycota (38%), Zygomycota (3%), Glomeromycota (0.4%), Chytridiomycota (0.2%) and unclassified fungi (0.5%). The predominant Ascomycota classes included the Dothideomycetes (33%) and Eurotiomycetes (14%). In contrast, the Basidiomycota were primarily composed of the Ustilaginomycetes (13%), Tremellomycetes (10%), and Agaricomycetes (8%). Species that represented greater than 5% of all identified fungal sequences included Pithomyces chartarum, Aureobasidium microstictum, Aspergillus penicillioides, and Ustilago syntherismae.
Conclusions: The Sanger sequencing dataset demonstrated a broad spectrum of fungi that were recovered from the dust of a water damaged office environment. These data identify a previously overlooked fungal profile composed of Basidiomycota species. These fungi may contribute to occupants’ exposure in moisture damaged indoor environments.